Abstract

A stochastic analysis for the cross‐spectral density method of measuring acoustic intensity is presented. The analysis is based on the theory of linear mean‐square estimation as applied to stochastic processes and its generality is preserved through the use of some concepts from the theory of multidimensional stochastic processes. A general theoretical expression, in terms of spatial‐correlation and cross‐spectral density functions between two closely spaced microphones, is obtained for estimating acoustic intensity. The stochastic analysis presented in this paper highlights the effects of incorporating finite difference approximations. It is also shown that how the present cross‐spectral density formula can be reduced to an exact expression for the specific case of plane‐wave sound field.